Fuel injection nozzles



Nov. 29, 1960 G. WHITEHURST FUEL INJECTION NOZZLES Filed NOV, 17, 1959United States Patent FUEL INJECTION NOZZLES George Whitehurst, 37 MertonRoad, Harrow, Middlesex, England Filed Nov. 17, 1959, Ser. No. 853,652

Claims. (Cl. 239-453) This invention relates to fuel injection nozzlesand aims at providing a fuel injection nozzle which will provide asatisfactory atomised fuel spray both at low and high fuel deliverieswithout entailing an excessively high operating pressure at maximumdelivery.

The present invention aims at avoiding this drawback and at providing afuel injection nozzle which operates within acceptable pressure limitsboth at low and at high delivery rates whilst at all times ensuringhighly eflicient fuel atomisation.

According to the present invention there is provided an injection nozzlefor fluids, wherein a nozzle body has an inlet for the fluid to beinjected and an outlet for the fluid, the inlet and outlet being incommunication with a chamber in the body, and wherein a valve stemcontained within the body carries at one end a valve adapted to seatwithin said outlet and at the other end an apertured disc containedwithin said chamber and normally sepaarted from a washer of resilientmaterial contained within said chamber but capable of engaging saidwasher when said valve is unseated, there being spring means urging saidvalve into its seated position, the arrangement being such that at lowdelivery rates of said fluid, the fluid flows into said chamber, throughthe apertures in said disc and unseats said valve against the action ofsaid spring means so as to be injected, but that at high delivery ratesthe pressure of the fluid additionally causes said disc to engage theresilient washer whereby further unseating of the valve is governed bysaid washer and said spring means.

In order to enable the invention to be more readily understood,reference is made to the accompanying drawing which illustratesdiagrammatically and by way of example, a longitudinal section through afuel injection nozzle.

In said drawing, 1 denotes a nozzle body which is internallyscrew-threaded at 2 to receive an externally screw-threaded connectornipple 3, having an internal bore 4 terminating in a cylindrical chamber5. The nipple connector 3 is held in position on the nozzle body 1 by alock nut 6 and is sealed from leakage by a metal ring 20.

The nozzle body 1 is provided with a lower screwthreaded portion 7adapted to be screwed into the fuel application orifice (not shown).

Located in the chamber 5 is a detachable valve housing 8 provided withan internal bore 9 through which passes a valve stem 10, carrying at itslower end in a valve 11 seating on a corresponding machined surface 12within the outlet of the valve housing 8.

At its upper end the valve stem is screw-threaded at 13 and passesthrough an internally screw-threaded metal disc 14 screwed on the valvestem 10 and having angularly drilled apertures 15 permiting fuel to passinto the space beneath the disc 14. The valve stem 10 is maintained inposition on the disc 14 by a lock nut 16. The central bore in the valvehousing 8 is counter-bored at 17 and is adapted to receive a distancesleeve 18 of steel or like non-compressible material and a helicalspring 19 bearing at its lower end against the distance sleeve 18 and atits upper end against the underside of the disc 14.

Located in the bottom of the chamber 5 beneath the disc 14 is a ring 22of synthetic rubber or like resilient material which is normallyseparated from the underside of the disc 14 by a small free space 23.

When the nozzle is operated at low delivery rates, fuel enters thechamber 5 through the inlet .bore 4. The fuel then passes through theapertures 15 in the disc 14, into the counter-bored portion 17 of thevalve housing 8 down to the valve seat 11.

The fuel pressure built up by the passage of the fuel to the valve seat11 ultimately forces the valve 11 away from the valve seat 12 counter tothe pressure of the helical spring 19, so that the fuel is injected, thefree space 23, however, remaining open.

However, at high delivery rates the valve 11 is forced further away fromits seat against the pressure of the helical spring 19, thereby causingthe disc 14 to move downwards into engagement with the synthetic rubberor the like ring 22, and thus closing the free space 23. On encounteringthe rubber ring a change takes place beween the upper surface area andthe lower surface area of the disc 14, presented to the fuel and thefuel tends to press the disc 14 and with it, the valve 11, counter tothe force of the helical spring 19, and the synthetic rubber ring 22,thereby ensuring a satisfactory delivery and atomisation of fuel at highdelivery rates.

It will be seen that the properties of-the nozzle illustrated arecapable of adjustment within wide limits, for example, by altering theposition of the lock nut 16 and the disc 14, by altering thecharacteristics of the spring 19, by replacing the distance sleeve 18 byone of different length by the interposition of shims between thedistance sleeve 18 and the helical spring 19, and by altering thecharacteristics of synthetic rubber ring 22.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent, is:

1. An injection nozzle for fluids, wherein a nozzle body has an inletfor the fluid to be injected and an outlet for the fluid, the inlet andoutlet being in communication with a chamber in the body, and wherein avalve stem contained within the body carries at one end a valve adaptedto seat within said outlet and at the other end an apertured disccontained within said chamber and normally separated from a washer ofresilient material contained within said chamber but capable of engagingsaid washer when said valve is unseated, there being spring means urgingsaid valve into its seated position, the arrangement being such that atlow delivery rates of said fluid, the fluid flows into said chamber,through the apertures in said disc and unseats said valve against theaction of said spring means so as to be injected, but that at highdelivery rates the pressure of the fluid additionally causes said discto engage the resilient washer whereby further unseating of the valve isgoverned by said washer and said spring means.

2. A nozzle as claimed in claim 1, wherein said disc is adjustablymounted on said valve stem.

3. A nozzle as claimed in claim 1, wherein said spring means comprises ahelical spring surrounding said valve stem in a recess in said body.

4. A nozzle as claimed in claim 3, wherein said spring rests on areplaceable distance sleeve in said recess.

5. A nozzle as claimed in claim 1, wherein the nozzle body is ofmulti-part construction.

References Cited in the file of this patent FOREIGN PATENTS 548,567Italy Sept, 26, 1956

